Dr. Patel
Allergies are one of the most common health conditions in the world, and a major cause of illness in the United States. In fact, allergies cause about two million missed school days each year. Dr. Green, what are allergies and what do parents need to know about them?

Dr. Green
Well, Dr. Patel, allergies are abnormal immune system reactions to something that's harmless to most people, such as dust, pollen, or certain foods. When a person has an allergy, their immune system mistakenly believes that a normally harmless substance is attacking the body.

Substances that cause allergic reactions are known as allergens. Allergens can be inhaled, eaten, or injected, or they can come into contact with the skin.

Some common allergens include:

  • Pollens from trees, grasses, and weeds
  • Molds, both indoor and outdoor
  • Dust mites that live in bedding, carpeting, and other items
  • Animal dander
  • Some foods and medicines
  • Venom from insect stings, and
  • Latex

Mild allergic reactions can include itching, sneezing, runny nose, watery eyes, or hives. More severe allergies can cause diarrhea, vomiting, and in the most serious cases, a life-threatening reaction called anaphylaxis. Anaphylaxis can happen quickly and involves:

  • Hives
  • Swelling of the face, mouth, hands, and feet
  • Trouble breathing
  • Wheezing, and
  • Dizziness

Anaphylaxis can lead to shock and even death.

Children with a family history of allergies have an increased risk of developing allergic disease. But if you, your partner, or one of your children have allergies, it doesn't mean that all of your children will get them. And usually someone doesn't inherit a particular allergy, just the likelihood of having allergies.

Some children have allergies even if no family member is allergic, and those who are allergic are likely to have more than one type of allergy.